But faced with a kill-or-be-killed situation, law-abiding citizens can’t always weigh – or even know – all of the consequences of their actions.

“I think most of the time it’s a situation where they feel as though they didn’t have much of a choice,” said R. Scott Stehouwer, chairman of Calvin College’s psychology department.

“After the shock wears off, even the fear, the anger or outrage … we try to figure out: What in the world just happened?” he said.

“I don’t think any of us consider ourselves a killer.”

Self-defense killings are relatively rare. Officially, Michigan recorded 117 cases from 2000 to through 2010, though an MLive Media Group investigation found dozens more that were not included in records.

With relatively few cases, those involved in a justifiable homicide can feel alone.

JUSTIFIED TO KILL

“What often happens with people who shoot and kill, they feel very isolated,” Stehouwer said.

“They’re the only ones in that situation. They are the ones who committed the act. Other people say, ‘It’s (justified),’ but it’s easy to feel very alone.”

They second-guess themselves, and replay events in their minds. Taking a life, no matter how justified, isn’t taken lightly by most in such situations.

“We do recognize that people who are killed may very well deserve that,” Stehouwer said. “But they’re still people. They have families and they have people who love them. On TV shows, it’s over and done with. In real life, there are funerals for these people. There are families, there are friends – there are loved ones.

“Regardless of how justified it is, it is still a death.”

Researchers on killings by otherwise law-abiding people - whether soldiers, police or civilians - have found the aftershocks can include conflicting emotions: elation at surviving, and guilt at having to violate an ingrained aversion against killing another human.

MLive file photoThe wife of Cedar Springs homeowner Bob Clarke says her husband was depressed and possibly suicidal after he fatally shot a would-be intruder in 2001. Clarke, seen here a short time later, died in 2008 from cancer.

Left unresolved, this "cognitive dissonance" can lead to anxiety and depression, according to research by Massad Ayoob, a nationally known firearms and self-defense instructor.

Another nationally known self-defense expert, author David Grossman, coined the term “killology” for his brand of research focusing on healthy people in killing circumstances.

Grossman, a former Army Ranger and retired lieutenant colonel, wrote, “On Killing: The Psychological Cost of Learning to Kill in War and Society.” While much of his focus ison police and the military, experts say untrained civilians are even less prepared to deal with the aftermath of such events.

Survivors also face another burden. By virtue of the experience, they confront their own mortality, the unsettling “fragility of life," Stehouwer said. "In an instant, it can be gone."

Stehouwer suggests those involved in such cases write their stories down. Then they won’t feel such a need to keep their experiences in the forefront of their minds. Knowing the experience is documented helps them put it in the past, he said.

One positive, Stehouwer added, is those who act in self-defense often receive deserved support from the community, and often conclude they did the right thing.

“We can say that, but on the inside, it’s a little different experience.”